cyrilinf_FR
New member
- Joined
- Feb 16, 2022
- Messages
- 2
Hello
First of all, sorry for my english i'm french
In 2020 i began a project for a first powerwall using old laptop cells. I built a first 160S14P, testing cells with 8 Littokala (1 is now dead)
Problem of this charger is they can't charge very low voltage cells (under 2v). So for the cells with low voltage i use an opus charger to bring cells around 3V and after that i can test them with the litto
Test process take long time, 2240 cells tests and record in an excel file
During the testing process i search a way to built the bank but i as i didn't find what i want i test and print them. Afraid by the heat each 2 cells the space is enlarge
But as for me it was not enought (i think) to evacuate the heat i take a computer 42 rack and build a drawer with fan
Weight is important but i strenghten it and it's ok. But i never use the fan because i have a large amount of cells and the room is cold in summer. So for a big powerwall no need to take heat cells in consideration
After testing the cells come the repack step and the bank creation. Each cell must go in a bank and the bank must have the same capacity. It's also take time to do that and check a second time again all the bank to correct errors.
I create the bus bar for the bank 25 mm² of copper
And once the bank are ok (4 bloks stick)
Have to solder bus to the cell. I use fuse wire to avoid problem, if one cell go wrong the fuse wire will deconnect it, for me it's safer but it take a LOT of time
The first powerwall in place (not connected)
At the top of the rack i install 3 fuse (150A), sum of the copper cable -> 52mm²
First powerwall take the 2 drawer, the second only one but 128SP14 only (with higher cells capacity)
I connect all with an hybrid inverter and link that with an arduino and to my domotic box (jeedom) to follow load / consumption / temperature / solar production ...
This is my house electrical consumption before and after (first powerwall go in production in june but i ever have solar pannel before without powerwall)
With the second powerwall and some change we decrease electrical consumption to 86% and will bring some change to push some load to the powerwall
It's work well and without BMS, i bought one but not easy to install in the rack and also due to the size of the powerwall. I check each bank and the last check show i need to balance some banks (but after more than 1 years it's appear normal)
Power wall 1 55,4v
4,2 3,98 3,99 3,99 3,98 3,96 3,87 3,85 3,94 3,95 3,97 3,93 3,95 3,98
power wall 2 55,5v
3,99 3,97 3,99 3,96 3,96 3,81 3,96 4.0 3,99 3,92 3,99 3,90. 3,96 4,1
I'am building a third powerwall but due to a lack of 18650 cells i test flat cells, the capacity is not really good but the flat design could be interesting i have to check if i can have lot of this cell laptop
This is some data about the powerwall
1st powerwall 160S14P / 2240 cells / 382 A by bank / average cells capacity 2386 mah
2nd powerwall 128S14P / 1209 cells / 305 A by bank / average cells capacity 2553 mah
First of all, sorry for my english i'm french
In 2020 i began a project for a first powerwall using old laptop cells. I built a first 160S14P, testing cells with 8 Littokala (1 is now dead)
Problem of this charger is they can't charge very low voltage cells (under 2v). So for the cells with low voltage i use an opus charger to bring cells around 3V and after that i can test them with the litto
Test process take long time, 2240 cells tests and record in an excel file
During the testing process i search a way to built the bank but i as i didn't find what i want i test and print them. Afraid by the heat each 2 cells the space is enlarge
But as for me it was not enought (i think) to evacuate the heat i take a computer 42 rack and build a drawer with fan
Weight is important but i strenghten it and it's ok. But i never use the fan because i have a large amount of cells and the room is cold in summer. So for a big powerwall no need to take heat cells in consideration
After testing the cells come the repack step and the bank creation. Each cell must go in a bank and the bank must have the same capacity. It's also take time to do that and check a second time again all the bank to correct errors.
I create the bus bar for the bank 25 mm² of copper
And once the bank are ok (4 bloks stick)
Have to solder bus to the cell. I use fuse wire to avoid problem, if one cell go wrong the fuse wire will deconnect it, for me it's safer but it take a LOT of time
The first powerwall in place (not connected)
At the top of the rack i install 3 fuse (150A), sum of the copper cable -> 52mm²
First powerwall take the 2 drawer, the second only one but 128SP14 only (with higher cells capacity)
I connect all with an hybrid inverter and link that with an arduino and to my domotic box (jeedom) to follow load / consumption / temperature / solar production ...
This is my house electrical consumption before and after (first powerwall go in production in june but i ever have solar pannel before without powerwall)
With the second powerwall and some change we decrease electrical consumption to 86% and will bring some change to push some load to the powerwall
It's work well and without BMS, i bought one but not easy to install in the rack and also due to the size of the powerwall. I check each bank and the last check show i need to balance some banks (but after more than 1 years it's appear normal)
Power wall 1 55,4v
4,2 3,98 3,99 3,99 3,98 3,96 3,87 3,85 3,94 3,95 3,97 3,93 3,95 3,98
power wall 2 55,5v
3,99 3,97 3,99 3,96 3,96 3,81 3,96 4.0 3,99 3,92 3,99 3,90. 3,96 4,1
I'am building a third powerwall but due to a lack of 18650 cells i test flat cells, the capacity is not really good but the flat design could be interesting i have to check if i can have lot of this cell laptop
This is some data about the powerwall
1st powerwall 160S14P / 2240 cells / 382 A by bank / average cells capacity 2386 mah
2nd powerwall 128S14P / 1209 cells / 305 A by bank / average cells capacity 2553 mah
Last edited:
Looks good, works good!